1. Field of the Invention
The invention relates to a vehicle seat. More specifically, the invention relates to a vehicle seat in which an operating member that is operated to tilt a seatback forward is fitted to a seat body such that the operating member is operated from behind the seat body.
2. Description of Related Art
There is a conventional vehicle seat that is structured to allow a rear-seat occupant to perform an operation for switching an operation mode to a walk-in mode in which a front seat is tilted and slid forward (hereinafter, referred to as “walk-in operation”). Japanese Patent Application Publication No. 2010-83343 (JP 2010-83343 A) describes a structure in which an operating member used to perform the walk-in operation is disposed at a side portion of a lower rear portion of a front seat. The operating member is coupled via a link mechanism to an operating shaft of a reclining mechanism that maintains a fixed reclining angle of a seatback. Owing to the link mechanism, an occupant is able to cancel the lock state of the reclining mechanism with a weak operating force to perform the walk-in operation. After completion of the operation, the operating member is returned to its original position in which the operating member is located before the operation, by a biasing force of a tension spring that is hooked on the link mechanism.
In the structure described in JP 2010-83343 A, the tension spring is used to bias two links, which are linked to each other, in such directions that the links move away from each other, that is, such directions that an angle between the two links increases. More specifically, the links have protruding portions that protrude in the respective directions in which the links move away from each other, and the ends of the tension spring are hooked on the respective protruding portions. Specifically, in one of the links, the tension spring is hooked on the protruding portion that is located at a position further outward than a connecting point, at which the links are connected to each other, in a direction in which the link extends. Accordingly, the required length of the link is longer than the length of a portion of the link, which actually transmits force, that is, an effective link length. This makes it difficult to obtain an effective link length that is long enough to further reduce an operating force required to operate the operating member.